Without limiting the scope of the invention, its background is described in connection with the removal of heat dissipated from high-powered electronic devices, associated with base station circuitry components as an example.
A base station provides a means of reception and transmission to and from wireless communication mobile units and provides an interface to a telecommunication network. For this purpose, base stations comprise a transceiver unit comprising an input for receiving signals to be transmitted, a signal processor for processing signals to be transmitted on a predetermined frequency channel, and a power amplifier for amplifying and feeding the signals to be transmitted to the transmitter unit's antenna.
High power levels generated in the transceiver's power amplifier cause increased temperature levels. If the power amplifier is not properly cooled, dramatic temperature increases could result in significant damage to the overall transceiver. Also, temperature increases generated within high performance semiconductors, such as the power transistor, could vary the electrical performance characteristics of the transceiver unit and cause the degradation of materials resulting in reduced reliability and device failure.
Typically, cooling in power amplifiers is accomplished using a large heat sink that includes cooling fins. This heat sink is directly attached to a flange of the power amplifier devices to provide low thermal resistance. Usually, at the temperature levels associated with base station power amplifiers, the passive cooling provided by the heat sink is not sufficient. Further cooling of power amplifiers may be accomplished by the use of natural airflow or by purposely applying cool airflow to the heat sinks to reduce their temperatures.
The basic idea with fan and fins is to spread heat over the surface of the heat sink enough so that it is possible to remove the heat with a relatively low airspeed fan. Use of the heat sink with fins and a fan has many shortcomings. In order to effectively remove heat generated from high-powered electronic devices at the temperature levels associated with base station power amplifiers, the heat sink would require a large surface area, resulting in an inefficient use of space. A base station comprises several power amplifiers and would require a separate fan for each amplifier. The result is an overall increase in expense for each base station and a decrease in system reliability. In the event that a fan used to cool such equipment fails, overheating could result in the destruction of base station equipment.
As may be seen, therefore, improved methods of removing generated heat from high-powered electronic devices, for example, those used in a base station environment could provide a commercially useful article and reduce replacement expenses, maintenance costs and inconvenience in sudden breakdown of base station system components.